Process for printing with vat-dyesttjffs mixed with cellulose esters or



Patented Apr. 23, 1 929.

UNITED STATES PATENTT'OFFICE'.

ERNST IPFEFFER, OF SCHWANHEIM-ON-THE-MAIN, GEIBMANY, ASSIGNOB TO GRASSELLI DYESTUFF CORPORATIONQOF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

, rnoonss FOR PRINTING WITH VAT-DYESTUFFS MIXED WITH cELLULosE ESTERS on,

ETHERS.

No Drawing. Application filed October 15, 1927, Serial No. 226,521, and in Germany October 2d, 1926.

The present invention relates to a process for printing with vat-dyestuffs and material im iregnated or printed with a vat-dyestutf mixed with a solution of a cellulose ester or cellulose ether. I

In printing fabrics with vat-dyestuffs, the dyestulf is thickened by means of a starch or gum solution and then printed with the addition of an alkali and a sulfoxylate. In order to fix the vat-dyestuff, the material is steamed after printing and theirwashed and finished. This process is suitable for material which is printed on the usual machines, but in printing by hand or by stencilling difiiculties arise as, contrary to machine printing, it is in this case often not possible to print the material and steam it as well in one day, and if the material is allowed to remain for along time before it is steamed, the sulfoxylate decomposes in the thinly printed layer so that 'a reduction during. the steaming operation cannot take place and the dyestuff will be fixed on the fiber only imperfectly .or even not at .all.

My invention is based on the discovery that these disadvantages are obviated-by mixing the dyestuff intimately with a'solution of a cellulose ester or cellulose ether i. e. of an organo-oxy derivative of cellulose, printing this mixtureon the material and treating the material, before steaming, with a solutionof a reducing agent, such as for instance of a sulfoxylate, and an alkali. Water-soluble cellulose-alkyl others have proved tobe particularly suitable for this purpose. By the treatment with the reduc ing agent and an alkali, the cellulose ester or ether is salted out and the dyestuif does not bleed into the unprinted parts. The usual starch or gum thickenings by themselves do not come into question for this purpose as they would easily bleed. By the new process the material may be printed and stored an later on developed, even after the lapse of a considerable time, a fact which is a great particularly with water-soluble cellulose alkyl-ethers, is also suitable for printing material by means of a printing machine of the type hitherto used only for paper-printing. On such machines, the printin rollers of which are engraved photograp ically, the

able for this purpose, because it permits the preparation of printing colors which con tain large quantities of dyestuff dissolved in solutions of cellulose esters or cellulose others. After printing, the material is treated with the quantity of reducing agent and alkali necessary for fixing thedyestuff and then steamed; in this way artistic printing effects are obtained ,which cannot be produced in the-same beautiful style on an ordinary machine for printingfabrics. I

The following examples serve to illustrate my invention, but they are not intended to limit it thereto:

1. The material is printed with the following printing color (by block-printing) Printing color.

200 grains of the black vat-dyestuff in paste form prepared accordingto German Patent No. 241,997. grams of water, grams of thickening M.

1' kilo.

Thickening M.

100 grams of methyl cellulose are dissolved in 900 grams ofcold water 1 kilo. 7

After printing, the material is padded wit the following solution: 1

. Padding liquor.

200 grams of Rongalite C 1: 1

. 80 grams of glycerine I 3( ,grams of dissolving salt B 120, grams of potassium carbonate 571) grams of water The material is then dried and steamed with wet steam for 5 minutes at 101 C. in a rapid-ager (Mather-Flatt freed from air, finally washed and soaped at the boil.

Instead of methyl cellulose there may also be used other water-soluble alkyl-celluloscs, for instance Water-soluble ethyl-cellulose.

2. The material is printed with. the following printing color Printing color.

200 grams of the black vat-dyestutl in paste form prepared according to German Patent No. 241,997, 100 grams of acetone, 700 grams of thickening A 1 kilo. Y Y

Thickening A.

80 grams of ethyl cellulose dissolved in 920 grams of acetone 1 kilo.

The material is further treated as indicated in Example 1.

3. The materialis printed with the following printing color:

Printing color.

100 grams of the dyestutl' in paste form prepared according to UQS. patent specification No. 753,659, 100 grams of benzene, 100 grams of alcohol, 700 grams of thickening B.

i kilo.

Thickening B.

80 grams of ethyl cellulose dissolved in 460 grams of alcohol and 460 grams of benzene I kilo.

After printing, the material is padded and finished as indicated in Example 1.

4. For printing on a deeply printing machine is used, for instance, the following printing color:

Printing color.

500 grams of the black vat-dyestufi' in paste form prepared according to German patent specification No. 241,997,

500 grams of thickening M (see Example 1).

1 kilo.

The material is further treated as above indicated.

In the following claims the term organooxy der vative of cellulose 1s tobc understood to comprise ethers and esters of cellulose.

stulfs, which comprises printing the mate-' rial'with a vat-dyestufi mixed with a solution of a cellulose ether, treating the material subsequently with a reducing agent and an alkali, and finishing it by one of the usual methods.

3. The process for printing with vat-dyestuffs', which comprises printing the material with a vat-dyestulf mixed with an aqueous solution of a cellulose ether, treating the material subsequently with a reducing agent and an alkali, and finishingit by one of the usual methods.

4. The process for printing with vat-dyestufls, which comprises printin the material with a vat-dyestufi mixed with an aqueous solution of methyl cellulose, treating the material subsequently with a reducing agent and an alkali, and finishing it by one of the usual methods. I I

In testimony whereof, I aifix my signature.

ERNST PFEFFER. 

